biggs--boo, hiss.
Actually, I find the companionship of my therapeutic friend Esmeralda to be something I would find extremely relaxing on flights. She is tranquil, a calming presence to all who know here, extremely affectionate, packs her own trunk, and works for peanuts. I can imagine how, when I would otherwise be completely tramatized by the stress of boarding by row, uncomfortable seats, tight quarters, sometimes nasty FAs (notice that I said "sometimes"), her gentle touch upon my fevered brow would render me fit to fly. So, if ya got yer pig,howcum I can't have my pachyderm?
This pig business is so far from reality, you really have to wonder what the hell the clowns that let the animal on, and the even more clownly FAA types who think this was a good idea, could have been using for intelligence--certainly not the recommended daily minimum (except shared amongst the lot of them).

Good grief.

And, anybody can sue anybody for any reason, but that doesn't mean that you deal with situations like this as though you were woried about finding yourself in court down the road. The other side of that would be to think about the lawsuits that would ensue (hah--pun!) if anyone were injured as a result of having this animal on the aircraft--a far more likely scenario.
Not that I have anything against pigs--they are great with eggs. I just object to stupidity (yes, I know, you can't get away from it).

In point of fact (as far as I know) there are only two universals wherever humans (pc) are or will be: hydrogen, and stupidity. Both present in abundance in this instance.